Everything I know about data centres and SOA and uptime is laughable at google or twitter scale. Likewise, everything I know about HR and culture and hiring practises is laughable at "workforce bigger than some countries" scale.
The vast majority of that 1m+ employees are low-skilled wage laborers. Finding 3000 high-skill engineers is definitely a monstrous task. Twitter is 7+ years old and they're only at ~1600 employees about half of which are engineers.
Everything I know about data centres and SOA and uptime is laughable at google or twitter scale. Likewise, everything I know about HR and culture and hiring practises is laughable at "workforce bigger than some countries" scale.